* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
#root {
  background: #989898;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}
.app {
  width: 800px;
  height: 450px;
  border: 4px solid #F4B03E;
  display: flex;
  background: #BCBCBC;
}
.keyboard {
  flex: 6;
  display: flex;
  flex-wrap: wrap;
  padding: 40px;
  .keyboardItem {
    width: calc((100% - 20px) / 3);
    background: #8B8B8B;
    border-radius: 5px;
    margin-right: 10px;
    margin-top: 10px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-weight: bold;
    box-shadow: 2px 2px 3px 1px #000000;
    user-select: none;
    &:nth-child(3n) {
      margin-right: 0;
    }
    &:nth-child(1), &:nth-child(2), &:nth-child(3) {
      margin-top: 0;
    }
    &.down {
      box-shadow: none;
    }
    &.on {
      background: #F4B03E;
    }
  }
}
.controller {
  flex: 4;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  .title {
    width: 100px;
    height: 40px;
    background: #ccc;
    margin: 15px 0;
    text-align: center;
    line-height: 40px;
  }
}
.switch {
  width: 80px;
  h4 {
    text-align: center;
    line-height: 30px;
  }
  p {
    width: 100%;
    height: 30px;
    background: blue;
    padding: 4px;
    cursor: pointer;
    span {
      display: block;
      width: 30px;
      height: 22px;
      background: #000000;
      color: #ccc;
    }
    &.on {
      span {
        transform: translateX(42px);
      }
    }
  }
}
.volume {
  width: 100%;
  height: 6px;
  background: #333333;
  margin: 15px 0;
  position: relative;
  .line {
    width: 100%;
    height: 100%;
    background-image: linear-gradient(to right, #44cdff5c 0%, #ff4100 100%);
  }
  .circle {
    position: absolute;
    left: 50%;
    top: -3px;
    width: 12px;
    height: 12px;
    background: #fff;
    border-radius: 50%;
    cursor: pointer;
  }
  &.down {
    .circle {
      transform: scale(1.5);
    }
    .line {
      transform: scale(1, 1.5);
    }
  }
}